Differential Diagnosis for Single Node Cervical Lymphadenopathy in a 12-Year-Old Boy

Single Most Likely Diagnosis

• Infectious Cervical Lymphadenitis: This is the most common cause of cervical lymphadenopathy in children, often resulting from a viral or bacterial infection, such as streptococcal pharyngitis. The presence of tenderness supports this diagnosis, as infectious causes are more likely to be painful.

Other Likely Diagnoses

• Reactive Lymphadenitis: This condition occurs as a reaction to a nearby infection or inflammation, not necessarily involving the lymph node itself. It's common in children and can be tender.
• Tuberculous Lymphadenitis: Although less common in some regions, tuberculosis (TB) is a significant cause of lymphadenopathy worldwide, especially in areas with high TB prevalence. It can present with tender lymph nodes, especially if the infection is progressing.
• Cat-Scratch Disease: Caused by Bartonella henselae, this condition typically follows a cat scratch or bite and can lead to tender lymphadenopathy, usually in the neck.

Do Not Miss Diagnoses

• Lymphoma: Although less common, lymphoma (Hodgkin or non-Hodgkin) is a critical diagnosis not to miss, as it requires prompt treatment. It can present with painless lymphadenopathy but can also be tender, especially if there's an associated infection.
• Metastatic Disease: Certain cancers, like neuroblastoma or thyroid cancer, can metastasize to cervical lymph nodes. While rare in this age group, missing such a diagnosis could have severe consequences.

Rare Diagnoses

• Kikuchi-Fujimoto Disease: A rare, self-limiting condition that can cause cervical lymphadenopathy, often accompanied by fever and night sweats. It's more common in young women but can occur in males.
• Kimura Disease: A chronic inflammatory disorder that can cause lymphadenopathy and eosinophilia, more commonly seen in Asian males. It's rare and typically presents with painless lymph node enlargement.
• Sarcoidosis: Although rare in children, sarcoidosis can cause lymphadenopathy among other systemic symptoms. It's essential to consider in the differential diagnosis due to its potential for multi-organ involvement.

Each of these diagnoses has a different approach to management and treatment, emphasizing the importance of a thorough diagnostic workup to determine the underlying cause of the cervical lymphadenopathy.